James livingston and john kennedy



mi) Model.) v J. .LIVINGSTON 8v J. KENNEDY.

RELIEF VALVE EOE ENGINES.

No. 269,301. C Patented Deo. 19, 1882.

'TV/bie/.ssas. .T7125.61111115.57-v

N. Pinna Phuwumogmpnor, wmingm. nc.

UNITED STATES ATENT OFFICE.

RELIEF-VALVE FOR ENGINES.

SPECIFICATION forming part of Letters Patent No. 269,301, dated December 19, 1882. Application filed August 10, 1882. (No model.)

To all whom it may concern: l

Beit known that we, JAMES LIVINGSTON and JOHN KENNEDY, both subjects of the Queen of Great Britain, residing at the city of rIoronto, in the county of York, in the province of Ontario, Dominion of Canada, have jointly invented certain new and useful Improvements in Relief-Valves for Engines, of which the following is a specification.

The object of the invention is to provide a main valve for steam and other engines which will admit the steam into the cylinder without any retarding pressure on itself, and in which provision is made to relieve the engine-piston from back-pressure caused by the engine pum ping air when running light; and it consists in a double-ended piston-shaped valve adapted to work within an open ended cylindrical chamber formed within the main steam-chest, and provided with suitable steam inlet and exhaust ports, an auxiliary relief-valve being applied thereto, as hereinafter more particularly explained.

Figure 1 is a sectional View of an enginecylinder provided with our improved balanced valves. Fig. 2 is a detail view of the valves.

In the drawings, A is the steam-cylinder, which, with the piston-head and pistou-rod, is of substantially the usual construction.

U are two pistons mounted upon a spindle, C', and forming a double-ended piston-shaped valve placed within a cylindrical chamber formed within the steam-chest.

E are the steam-inlet ports to the cylinder from the valve-chamber',and F is the exhaustport. I

As both ends of the cylindrical casingGare open, the pressure of steam Ais equal and continuous at each end of the valve, and as the casin g G protects the circumference of the valve from pressure it is therefore perfectly balanced andA will perform its duty without appreciable friction.

The operation of the valve is so clearly shown by the drawings that it is unnecessary to describe it further than to say that as the valve is moved to and fro steam is alternately admitted to and exhausted from the cylinder, and the valve, being, as before stated, perfectly balanced, moves with but little friction, and therefore with great economy of power.

When our improved valve is applied to a locomotive we make the following provision to l prevent the back-pressure caused by the engine pumping ai-r when the steam is cut Off and the engine running free downgrade. The said provision consists of an automatic safety relief-valve, H, placed in a chamber formed in the top'of the steam-chest, which chamber is connected by the pipes I to the steam-ports E, connecting the steam chest and cylinder.

J is a spiral spring placed below the valve H for the purpose of holding it against its seat, closing the connection between the interior of the steam-chest and the two pipes II', the steam-pressure within the steam-chest imparting the pressure necessary to insure a steam-tight joint. When the steam is cut off from the steam chest the automatic reliefvalve H may be easily pressed clear of its seat, as the spiral spring J is designed merely to support the weight of the valve. When the engine is running without steam the air within the cylinder is compressed by the movement of the piston, having no exit through the ports E from the point Where the steam is out Oli' till it commences to exhaust. The backpressure thus produced injuriously affects the working of the engine unless means are provided to permit the escape of the lair being com pressed.

When our automatic relief-valve is applied the air is forcedby the piston up through theV pipe I till it reaches the valve H, and, the pressure of the air thus forced being suflicient to push the valve H clear of its seat, the airis permitted to continue its passage down through the other pipe, I', till it reaches thepport E leading to the cylinder at the opposite end of the piston, where a partial vacuum has been formed by the movement of the piston.

What -We claim as our invention is- 1. In a relief-valve, and in combination with the valve-chamber having arelief-chamber and port-connections with the main cylinder, a series of pipes connecting such ports and reliefchamber,and a spring-valve operating in such chamber, as and for the purpose set forth.

2. In a steam-chest having pipe-connections I I with the ports E, the relief-valve H and spring J, as set forth.

. JAS. LIVINGSTON.

. J. KENNEDY. Witnesses:

OHAs. G. BALDWIN, LEWIS TOMLINSON.

IOC 

